Apparatus for continuous wet treatment of a textile web

ABSTRACT

Apparatus for the continuous wet treatment of a textile web is disclosed, wherein the web is guided along a zig-zag path through a bath which is formed by treatment liquid flowing in counter current to the direction of movement of the textile web. The bath is contained in a channel shaped vessel, and a plurality of perforated deflecting rollers are positioned within the vessel and form between them a zig-zag-like path for guiding the textile web through the vessel and thus through the bath in meander-like manner. Nozzles are located within the vessel adjacent one of said rollers, the nozzles having a slot-like discharge opening which, when a textile web moves through the vessel, extends above the web and over substantially the entire width of the web. The discharge opening of the nozzle discharges treatment liquid in the form of a jet-like stream which impinges against the web in a direction substantially perpendicular to the plane of the web and to the axis of the roller beneath the web, while forming an acute angle with the longitudinal axis of the channel shaped vessel with the open side of the acute angle pointing in the direction in which the web is withdrawn from the vessel.

United States Patent 1191 Schroeder APPARATUS FOR CONTINUOUS WET TREATMENT OF A TEXTILE WEB [75] Inventor: Peter Schroeder, Ami, Switzerland [73] Assignee: Paul Weber A.G., Rothrist,

Switzerland [22] Filed: Aug. 23, 1972 [21] Appl. No.: 283,042 1 Related US. Application Data [63] Continuation-in-part of S81. No. 14,361, Feb. '26,

1970, Pat. No. 3,690,814.

[30] Foreign Application Priority Data Nov. 20, 1973 Primary ExaminerWilliam 1. Price Att0rney-David Toren et a1.

[5 7] ABSTRACT Apparatus for the continuous wet treatment of a textile web is disclosed, wherein the web is guided along a zig-zag path through a bath which is formed by treatment liquid flowing in counter current to the direction of movement of the textile web. The bath is contained in a channel shaped vessel, and a plurality of perforated deflecting rollers are positioned within the vessel and form between them a zig-zag-like path for guiding the textile web through the vessel and thus through the bath in meander-like manner. Nozzles are located within the vessel adjacent one of said rollers, the nozzles having a slot-like discharge opening which, when a textile web moves through the vessel, extends above the web and over substantially the entire width of the web. The discharge opening of the nozzle discharges treatment liquid in the form of a jet-like stream which impinges against the web in a direction substantially perpendicular to the plane of the web and to the axis of the roller beneath the web, while forming an acute angle with the longitudinal axis of the channel shaped vessel with the open side of the acute angle pointing in the direction in which the web is withdrawn from the vessel.

6 Claims, 2 Drawing Figures APPARATUS FOR CONTINUOUS WET TREATMENT OF A TEXTILE WEB CROSS REFERENCE TO PRIOR APPLICATIONS This is a continuation-in-part of co-pending application Ser. No. 14,361, filed on Feb. 26, 1970 and now US. Pat. No. 3,690,814.

FIELD OF INVENTION The invention is directed to apparatus for the continuous wet treatment of a textile web, wherein the web is guided along a zig-zag path through a bath formed by treatment liquid which flows in counter current to the direction of movement of the web, and wherein the bath is contained in a channel-like vessel in which a plurality of perforated deflecting rollers are positioned, the deflecting rollers forming between them a zig-zaglike path for guiding the textile web through the vessel and thus through the bath in meander-like manner.

BACKGROUND INFORMATION ANDPRIOR ART Known methods for the wet treatment, such as washing, bleaching, steaming, dyeing, impregnating, mercerizing, etc. of textile webs, such as webs of fabrics, knits, mats, etc., are usually based on the principle of the so-called roll vats, and have a relatively low efficiency.

To intensify the wet treatment processes, it has been proposed to combine repeated squeezing or extraction with repeated bilateral spraying of the textile webs. While these measures result in a certain increase in the efficiency of the wet treatment, they entail a considerable disadvantage in that the textile material, subjected to these treatments, undergoes heavy mechanical stress, so that these methods are unsuitable for delicate textiles. Further, the bath consumption is disproportionately high. Moreover, in many cases it is not desirable that the textile material come in contact with the atmosphere during the treatment.

One known method of this last-mentioned type essentially comprises guiding the material to be washed alternately, in zig-zag fashion, upwardly from the bottom over deflecting rollers, and charging it, during its passage between the rollers, with a treatment liquid, preferably from spray pipes.

In another known method, the textile material is immersed in the treatment bath during the entire treatment. In this procedure, it is sought to intensify the effect of the bath on the textile material in various ways, for example in that a flow of the bath is produced to run counter to the direction of movement of the textile web, or by vibrators, etc.

In the known methods, or in the apparatus developed for practising the methods, the webs are moved through the bath in unsupported relation over longdistances, and this precludes the treatment of very delicate fabrics. It also precludes tension-free treatment, such as is very often required.

For the wet treatment of textile webs, it must be noted, for one thing, that it is determining, for the quality of the treatment, that the bath concentration be distributed as evenly as possible over the width of the textile web. This can be attained by bath turbulence or through mixing, for example cycling of the treatment bath. Another problem is to get the treatment liquid really to the fiber or into the fiber. The bath particles must essentially pass through two zones, namely at first the boundary layer around the moving fiber and then, in the case of cotton, the actual fiber walls or, in synthetic material, the homogeneous fiber. The penetration of these zones occurs by diffusion. Such diffusion processes are known to be relatively slow and to have a disadvantageous effect on the economic efficiency of an installation. It has therefore been tried to shorten the treatment times as much as possible.

On the basis of Ficks first law of diffusion, it isfound that the rate of diffusion is proportional to the concentration gradient. Ficks law of difi'usion may be stated as follows:

dm/Fdt D'dc/dx, wherein dm diffusing quantity F surface to be traversed dt diffusion time dx diffusion path dm/Fdt rate of diffusion D diffusion constant dc/dx concentration gradient dc concentration difference.

To obtain as favorable as possible a solution in terms of engineering, an attempt must be made to influence the values on the right side of the above equation in such a way that the entire expression becomes a maximum. However, such maximization of the rate of diffusion must not simultaneously lead to high operational costs, but should result in an increase of efficiency. The concentration gradient dc/dx can be made a maximum, from the beginning tothe end of the process, if the concentration difference between the bath and the fabric is continuously maintained at as high as possible a value. It follows from this that the textile web must, during the entire process, be immersed in the bath, and the bath must be guided in a continuous counter current relative to the textile web. This results in a singlebath process.

In order, for economic reasons, to make the diffusion paths dx as short as possible, the moving bath must be applied directly on the individual fibers, in order that the concentration difference between the surface and the interior of the fiber will become a maximum and the respective chemicals can diffuse quickly. However, since the fabric web moving in the liquid has a relatively thick boundary layer, it is necessary to break through this layer as quickly and as thoroughly as possible to obtain the desired treatment effect.

SUMMARY OF THE INVENTION Briefly and in accordance with this invention, apparatus for the continuous wet treatment of a textile web of the indicated kind is characterized in that at least one side slot or wide band nozzle is arranged within the bath which nozzle extends above the web and over substantially the entire width of the web. In order to create a jet of treatment liquid, this nozzle is arranged in such a manner that its discharge opening discharges treatment liquid in the form of a jet-like stream which impinges against the web in a direction substantially perpendicular to the plane of the web and to the axis of the roller beneath and supporting the web, while at the same time forming an acute angle with the longitudinal axis of the channel shaped vessel with the open side of the acute angle pointing in the direction in which the web is withdrawn from the vessel.

Due to the particular arrangement of the wide slot or wide band nozzle or nozzles, the discharged jet exerts not only a superior penetrating action on the rollersupported web but at the same time facilitates or even generates the counter flow of the treatment liquid within the vessel. For this reason, the arrangement of special pumps or the like means for causing the desired counter flow is rendered unnecessary. Thus, the discharged jet, by forming an acute angle with the longitudinal axis of the vessel, the open side of the angle pointing in the direction of withdrawal of the web from the vessel, facilitates or even generates the counter flow of the treatment liquid within the vessel. Due to the fact that the jet at the same time impinges against the web in a direction which is substantially perpendicular to the surface plane of the textile web at a location where the opposite face of the web is supported by one of the deflecting rollers, the penetration of the jet through the roller-supported web takes place not only efficiently but in an advantageous manner. The discharged jet thus exerts not only an optimum penetration effect on the textile web but at the same time supports or generates the counter flow in the vessel. In this context it should be appreciated that in prior art arrangements, penetration of the boundary or interface layer between the textile web and the treatment liquid has been extremely difficult. By contrast, in the present arrangement, the boundary or interface layer is successfully penetrated by the impinging jet of treatment liquid.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention.

IN THE DRAWINGS FIG. 1 is a vertical sectional view through one embodiment of an apparatus of the invention; and

FIG. 2 is a vertical sectional view through a second embodiment of the inventive apparatus.

Referring now to FIG. 1, a substantially U-shaped or channel shaped upright vessel 1 accommodates a number of rotatable deflecting rollers 2 and 3. The number of deflecting rollers 2 and 3 will be dependent on the size of the vessel. Generally, the largest possible number should be arranged. The deflecting rollers 2 and 3 are arranged in the two vertical legs of the vessel 1 in the form of two rows of rollers, the two rows staggered or off-set relative to each other. All the deflecting rollers 2 and 3 have perforated surfaces, so that treatment liquid contacts the textile web from both sides. The perforations additionally prevent the build-up of a liquid cushion between the textile web, indicated by reference numeral 14, and the deflecting rollers 2 and 3. Such build-up ofliquid cushion would increase the tension in the fabric or web in an undesired manner since the effective circumference of the rollers would be increased.

The arrangement of the deflecting rollers 2 and 3 is chosen in such a manner that they are as closely adjacent as possible without, however, touching each other. In this manner the free or unsupported path of the textile web 14 between the rollers is reduced, and the web 14 passes through the vessel while being supported by the roller surfaces most of the time. The textile web 14 is guided around the deflecting rollers 2 and 3 in meander-like manner and passes through the apparatus or vessel 1 in the direction of the arrow indicated in FIG. 1. The vessel 1 is filled with treatment bath or liquid. While the web thus passes through the vessel, it is treated by the bath liquid in the desired manner. Since the rollers 2 and 3 are situated very close to each other, the looping angle of the web around the rollers is relatively large and exceeds at most of the rollers Due to this particular positive guiding of the web 14 around the rollers 2 and 3 and through the bath, wherein the web is deflected in opposing direction in alternate manner, an opening and a closing is accomplished, which is particularly important for the penetration of the treatment liquid through the boundary or interface layer. This is so because when the fabric web is curved or bent, the fiber interstices on the inner side are closed, and liquid positioned therein is thus squeezed out. By contrast, during the immediately following subsequent deflection, the textile web 14 is deflected into the opposite direction or side, and the previously closed interstices are now opened. The fiber interstices which are located on the outside are thus enlarged and draw in liquid from the adjacent bath supply. In this manner an exchange flow is created in the boundary layer which, with the usual fabric roughnesses is relatively thick. This exchange flow extends between the fiber surfaces and the boundary layer surfaces. In this manner the desired concentration gradient is produced directly at the fiber surfaces. This is in contrast to conventional procedures carried out with prior art apparatus wherein the treatment liquid which is located at the fiber surfaces, exhibits approximately the same concentration as in the fibers themselves. In prior art procedures, a concentration difference in respect of the surrounding liquid can only be detected towards the outer extremity of the boundary layer. With the prior art, conventional apparatus of the indicated kind, the effect of the treatment liquid within the relatively thick boundary layer can, however, occur by way of relatively'slow diffusion only.

In accordance with the invention a number of wide slot or wide band nozzles are arranged in the bath as seen in FIG. 1. The discharge openings extend over substantially the entire width of the textile web 14. Wide slot or wide band nozzles of the kind suitable for the inventive purposes have been disclosed in my previous US. Pat. No. 3,605,454, contents of which are expressly incorporated herein. The specific structure of the relatively large energy expenditure which is required for operating such nozzles 4, only a relatively small number of nozzles 4 is being used. It will thus be noted that in FIG. 1, three such nozzles are being shown in each leg of the channel shaped vessel. The discharge openings of the nozzles 4 are directed in such a manner that the discharged jet of treatment liquid on the one hand impinges against the web in a direction substantially perpendicular to the plane of the web and to the axis of the roller beneath the web while on the other hand the jet forms an acute angle with the longitudinal axis of the channel shaped vessel, the open side of the acute angle pointing in the direction in which the web is withdrawn from the vessel, to wit, the direction of the arrow. The discharge opening of the nozzles is thus directed relative to the general direction of movement of the textile web so that the portion of the jet which is deflected, after impingement, from the web supports or generates the counter flow of the treatment liquid within the vessel. If the jet is sufficiently strong, the desired counter flow can be entirely generated by the jet and thus no additional pumps or the like need be provided.

It has been ascertained that it is advantageous to guide the textile web 14 through the treatment bath in a condition in which the least possible tension is present in the web. In the device here shown this is achieved by driving the rollers 2 and 3 in slip-free manner, for example by means of chains so that all the rollers necessarily always have to have the same speed. Further, the tension between the feed or drawing-in roller 5 and the remaining rollers, to wit, the deflection rollers 2 and 3 inclusive of the squeezing rollers 6 is advantageously controlled by means of a yieldingly mounted compensating roller 7.

The supply of treatment liquid to the vessel 1 is effected by means of a wide slot nozzle 8 which is situated directly below the squeezing rollers 6. The other wide slot nozzles 4 are connected for feeding purposes to a line 10, the jets emanating from these latter nozzles 4 facilitating or generating the mentioned counter flow of the treatment liquid.

For the purpose of drawing in or inserting the textile web 14, the walls 1 1 may be removed. The rollers 2 and 3 are preferably constructed as tubes and contain in their interior displacement bodies 12 in order to reduce the required bath quantity and to channel the treatment liquid.

In the embodiment of FIG. 2, the textile web 14 enters the apparatus at the lower end of the vessel 1. This requires a good sealing at the place of entry. The number and arrangement of the rollers and nozzles is dependent on the desired procedure and the nature of the textile material to be treated.

It is also within the scope of this invention to close the vessel at its top and to place it under excess pressure, for example by compressed air. In this manner the apparatus may be operated at bath temperatures of above 100 C.

What is claimed is:

1. In an apparatus for the continuous wet treatment of a textile web wherein the textile web is guided along a zig-zag path through a bath formed by treatment liquid flowing in counter-current to the direction of movement of the textile web:

a. a channel-shaped vessel adapted to contain said bath;

b. a plurality of perforated deflecting rollers positioned within said vessel and forming between them a zig-zag-like path for guiding the textile web through said vessel and thus through said bath in meander-like manner;-

c. at least one nozzle located within said vessel adjacent one of said rollers, said nozzle having a slotlike discharge opening which, when a textile web moves through said vessel, extends above said web and over substantially the entire width of said web, and

d. means for supplying treatment liquid to said nozzle, said discharge opening being adapted to discharge treatment liquid in the form of a jet-like stream which impinges against the web in a direction substantially perpendicular to the plane of the web and to the axis of the roller beneath the web while forming an acute angle with the longitudinal axis of the channel shaped vessel with the open side of the actue angle pointing in the direction in which the web is withdrawn from the vessel.

2. Apparatus as claimed in claim 1, wherein the vertical section of said channel shaped vessel is substantially U-shaped, substantially the entire space of said vessel being filled with said deflecting rollers, said deflecting rollers supporting said web during its travel through the vessel in substantially uninterrupted manner.

3. Apparatus as claimed in claim 2, wherein said deflecting rollers are arranged in two adjacent rows, with the rollers in each row being staggered relative to the rollers in the other row.

4. Apparatus as claimed in claim 1, wherein said deflecting rollers are tube-shaped, displacement bodies being arranged within the interior of said tube-shaped deflecting rollers.

5. Apparatus as claimed in claim 1, wherein the majority of said deflecting rollers is positioned within said vessel in such a manner that the looping angle of the web around said rollers during the passage of the web through the vessel exceeds 6. Apparatus as claimed in claim 1, wherein said vessel is an upright vessel, said deflecting rollers being arranged in rows and being mounted for rotation about horizontal axes, each roller in one row being laterally adjacent a gap between the pair of rollers in the other TOW. 

1. In an apparatus for the continuous wet treatment of a textile web wherein the textile web is guided along a zig-zag path through a bath formed by treatment liquid flowing in countercurrent to the direction of movement of the textile web: a. a channel-shaped vessel adapted to contain said bath; b. a plurality of perforated deflecting rollers positioned within said vessel and forming between them a zig-zag-like path for guiding the textile web through said vessel and thus through said bath in meander-like manner; c. at least one nozzle located within said vessel adjacent one of said rollers, said nozzle having a slot-like discharge opening which, when a textile web moves through said vessel, extends above said web and over substantially the entire width of said web, and d. means for supplying treatment liquid to said nozzle, said discharge opening being adapted to discharge treatment liquid in the form of a jet-like stream which impinges against the web in a direction substantially perpendicular to the plane of the web and to the axis of the roller beneath the web while forming an acute angle with the longitudinal axis of the channel shaped vessel with the open side of the actue angle pointing in the direction in which the web is withdrawn from the vessel.
 2. Apparatus as claimed in claim 1, wherein the vertical section of said channel shaped vessel is substantially U-shaped, substantially the entire space of said vessel being filled with said deflecting rollers, said deflecting rollers supporting said web during its travel through the vessel in substantially uninterrupted manner.
 3. Apparatus as claimed in claim 2, wherein said deflecting rollers are arranged in two adjacent rows, with the rollers in each row being staggered relative to the rollers in the other row.
 4. Apparatus as claimed in claim 1, wherein said deflecting rollers are tube-shaped, displacement bodies being arranged within the interior of said tube-shaped deflecting rollers.
 5. Apparatus as claimed in claim 1, wherein the majority of said deflecting rollers is positioned within said vessel in such a manner that the looping angle of the web around said rollers during the passage of the web through the vesSel exceeds 180* .
 6. Apparatus as claimed in claim 1, wherein said vessel is an upright vessel, said deflecting rollers being arranged in rows and being mounted for rotation about horizontal axes, each roller in one row being laterally adjacent a gap between the pair of rollers in the other row. 